This invention relates to an apparatus for the inhalation of medicinal agents or drugs present in pulverulent or liquid form.
The administration of pulverulent or liquid medicinal agents by inhalation for the treatment of diseases of the respiratory tract, for example, bronchial asthma and rhinitis, is well known.
These medicinal agents can be administered by atomizing them with the aid of compressed air, hot steam, or a propellant gas to form a liquid or solid aerosol, and then inhaling the aerosol. This mode of administration, however, has the disadvantage that a predominant portion of the medicinal agent does not enter the respiratory tract. Consequently, an accurate dosing of the medicinal agent is impossible. Moreover, this mode of administration has the disadvantage that a considerable proportion of the drug enters the gastrointestinal tract and is absorbed therein, which can then cause undesired side effects. Moreover, when using propellant gases, the patient is subjected to the effects of the inhalation of an extraneous foreign substance.
In order to avoid this deficiency, devices have been developed for the inhalation of pulverulent medicinal agents in which the pulverulent drugs are atomized by the patient inhaling air through the device containing the drug. See, for example, Belgian Pat. No. 804,645 and U.S. Pat. No. 3,795,244.
These conventional devices possess movable, in most cases, propeller-type parts driven by the inhaled air, which effect an atomization of the pulverulent medicinal agents. The objective of conducting the pulverulent drug into the respiratory tract can be extensively attained by the use of these devices. Yet, these conventional instruments have several disadvantages.
First, since a considerable proportion of the inhaled air serves to set in motion the atomizing device, the patient must inhale very vigorously, which often causes considerable discomfort for the patient.
Second, adherence of a portion of the powdery drug to the movable parts of the device during inhalation is unavoidable, so that an accurate dosing of the drug is difficult.
Third, the manufacture of such devices with movable components renders them relatively expensive to the large number of people suffering from respiratory diseases.
Finally, such conventional devices have the disadvantage that only such pulverulent drugs can be used therein which are in perferated capsules, and proper dispensing of the drug from the capsules by these devices is assured only if the drug has a particle size large enough to permit the particles to be readily removed therefrom.
These conventional devices are thus unsuitable for dispensing pulverulent micronized or liquid medicinal agents.
It is an object of this invention to provide a dispensing device which does not have these disadvantages.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.